LECTURE
NO. 16
Bio-Diversity
16.1
Bio-diversity and sustainable Agriculture
Biodiversity
Biodiversity refers to rich and diverse
energy of
living organisms of
all species, the genes they contain and the
ecosystem they
constitute.
“Biological diversity means the variability
among
living organisms from
all sources including, interalia, terrestrial,
marine and other
aquatic ecosystems and the ecological
complexes of which
they are part, this includes diversity with in
species, between
species and of ecosystems”
Thus biodiversity is considered at three
levels:
a) genetic
diversity
b) species
diversity
c) ecosystem
diversity
a) Genetic
diversity refers to the variation of genes between
different populations
of a species as well as between
species.
b) Species/organismal
diversity refer to the variety of living
species.
c) Ecosystem
biodiversity relates to the variety of habitats,
biotic communities
and ecological processes and the
enormous diversity
present within ecosystems interms of
habitat differences
and the variety of ecological processes.
Importance of biodiversity
Biodiversity is recognized as the most
important natural
resources, it
directly and indirectly influences and regulates the
functioning of the
other natural resources of soil, water and air in
the ecosystem.
Humans derive all of their food almost 40
percent of their
medicines, and
industrial products from the wild and
domesticated
components of biological diversity.
Human Impact on Biodiversity
Human interventions can alter biodiversity
directly and
indirectly through
changes in land, water and atmosphere.
Human impact is
greater than that of most natural processes that
lead to a decline in
biodiversity. The most significant human
impact on
biodiversity and also the earliest was the
domestication of
plants and animals for food which started more
than 10,000 years
ago.
The root cause of human-induced biodiversity
loss is
actually the manner
in which human society functions in the
present global
context with respect to its natural resources, trade
and economic systems,
and human and social values.
Human activities change biological diversity
globally in
two fundamental ways
1) by affecting a globally dynamic system
such as the
atmosphere directly and 2) through the collective
consequences of
individual effects in various places and at
various times
building up to globally significant impact. For
instance, global
warming is due to direct excessive emission of
green house gasses
from burning fossil fuels as well as to the
cumulative effect of
deforestation, land clearance and faculty
agricultural practices
in various parts of the world.
Reduction in Biodiversity and its ecological
Implications
The truly irreversible nature of the loss of
species and
genetic diversity is
the most serious cause for concern for human
beings. The high
intensity and rate of human Intervention
increase the threat
of a decrease in species populations. Which
can eventually lead
to their extinction. A decline in biodiversity
can result in a
perceptible deficiency in the quality and amount
of ecological
services provided by nature. Over exploitation of
both natural and man
made resources, such as timber extraction
from natural forests
and over utilization of crop lands, can lead to
the disruption of
ecosystem services and increased costs.
Importance of Agricultural Bio diversity
1. Recycling
of nutrients
2. Control
of microclimate
3. Regulation
of local hydrological processes
4. Detoxification
of waste and toxic chemicals
5. Regulation
of the abundance of desirable and
undesirable
organisms.
6. Soil
structure
7. Infiltration
and run off Soil erosion
8. Natural
pest and disease control
9. Pollination
and
10. Genetic Introgression and hybridization
Agricultural Intensification & biodiversity
Agricultural activities have three types of
impacts on
biodiversity.
1. They
alter the characteristics of natural ecosystems and
their constituent
species.
2. They
impact the species and genetic variability of the
chooses cultivated
species themselves and also their
nonfood components.
3. The
affect on and off farm non food bio diversity through
such adverse
physiochemical effects as erosion,
salinization and
pesticide pollution. The magnitude of
these impacts varies
with the intensity of the intervention.
The magnitude of these
impacts varies with the intensity
of the intervention.
Population pressure and the concomitant
decline in
per capital land
availability have made-productivityoriented,
chemically
intensive,
high-yielding-variety
monoculture
and irrigated
agriculture
unavoidable in large
parts
of the world. This
has caused
an incalculable
loss of
biodiversity
both on and off-farm
and at all levels.
Thus modern
agriculture has evolved as a major
threat to
biodiversity in general and to diversity of
importance to agriculture
itself.
Impact of biodiversity reduction on modern
agricultural
systems
Species diversity:-
Products of plant
origin make
up 93 percent of the
human diet and 3000 species are
regularly exploited
for food. However modern agriculture
has drastically
shrunk the vast food basket provided by
nature and put ot use
by humans over thousand of years.
Only 103 species contribute 90 percent of the
world’s plant food
supply just three crops Rice, wheat and
maize-account for 90
percent of the calories and 56
percent of the
proteins people derive from plants. The
other thousands of
species contribute the remaining 10
percent of the plant
food supply, though they have
considerable
importance in the diet of poor people
confined to more
isolated areas.
Reasons for the oversimplification of edible plant
species.
The factors responsible for the adoption of
and extremely
limited no. of
species for the food security of a large segment of
the global population
are diverse: some have been deliberate and
some by default. The
discovery and wide spread use of modern
technologies of
production such as fertilisers, Pest control
chemicals,
mechanization and high-yielding these countries in
terms of production
and productivity. Apart from the fact that
these regions are
home to much more limited species diversity.
Their commercial and
economic insects were saved by the wide
production and a part
of a few popular species of crops.
The adoption of similar strategies became
unavoidable in
developing to meet
the food scarcity.
Genetic erosion
Genetic erosion consists of the loss of genes,
gene
complexes and unique
combinations of genes that occur in
different land. The
primary cause of the less of genetic diversity
of the widely used
plant crops and vegetables is the wide
speed
adoption of a limited
number if modern varities that are generally
bred for higher
yield, resistance to insect pests and diseases, and
high performance over
a range of biophysical environment, thus
reducing the need for
specific local adaptations.
Further, advanced methods of cultivation using
fertilizers,
irrigation, and pest
control chemicals have lowered the demand
for land races, which
have evolved largely through careful
selection and area
adapted to marginal growing conditions.
Without a rich reserve of varietal diversity,
long term
sustainability and
food security and livelihoods of poor farmers
in complex, diverse
and risk prone areas will be jeopardized.
Modern agricultural
production practices have created
tensions related to
different aspects of agricultural biodiversity
such as
- Severe
reduction in the no. of species of food plants
cultivated.
- Loss
of genetic diversity of the presently cultivated crops
and vegetables.
- Destabilization
of pest species in agro ecosystems.
- Deficiency
in soul biodiversity and
- Erosion of cultural diversity, loss of
indigenous
knowledge of
traditional farming systems and
environmental
degradation.
Thus the immense
potential of soil biodiversity for agricultural
productivity and
sustainability is still undervalued and needs to
be understood and
harnessed. Assigning intellectual property
heights to biological
materials that have been nurtured and
developed over
thousands of years by traditional farmers is a
contentious issue and
cannot be divorced from considerations of
human ethics and
values.
***
Abbreviations
FAO - Food and Agriculture Organisation
WHO - World Health
Organisation
WCED - World commission of Environment
and Development
GLASOD - Global
Assessment of the Status of
Human- induced Soil
Degradation
NAEB - National
Afforestation and Eco-
development Board
ESP - Exchangeable Sodium Percentage
EC - Electrical conductivity
CGWB - Central Ground Water Board
WMO - World Meteorological Organisation
UNEP - United Nations
Environment
Programme
UNCED - United
Nations Conference on
Environment and
Development
WUA - Water Users
Association
NWDB - National Waste
Land Development
Board
USDA - United States
Department of
Agriculture
ICRISAT -
International Crop Research Institute on
Semi-arid Tropics
NABARD - National
Bank for Agriculture and
Rural Development
CGIAR - Consultative
Group for International
Agricultural
Research
IREP - Integrated Rural Energy Progrmme
WTO - World Trade Organisation
CFC - Chlorofluorocarbons
IFOAM - International
Federation for Organic
Agricultural
Movements
NDDB - National Dairy
Development Board
DFL - Disease Free Layings
NBPGR - National
Bureau for Plant Genetic
Resources
IPM - Integrated Pest Management
CSSRI - Central Soil
Salinity Research Institute
UNDP - United Nations
Development
Programme
KVIC - Khadi and
Village Industries Board
NPV - Nuclear Poly hedrosis Virus
VAM - Vesicular
Arbuscular Mycorrhiza
WALAMTARI -Water and
Land Management Training
Research Institute
CADA - Command Area
Development Authority
NPBD - National
Project on Biogas
Development
MPTS - Multipurpose
Trees systems
IPCC - Intergovernmental Panel on Climate
Change
WSSD - World Summit
on Sustainable
Development
CBD - Convention on Biological Diversity
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